An early start to hurricane season? And, tornado kills 3 in Missouri

The 2009 Atlantic hurricane season may get off to an early start. For the past two days, most of our reliable hurricane forecast models have been predicting the possibility of a subtropical depression forming near Florida or Western Cuba Monday - Thursday next week. An area of disturbed weather associated with a mid- to upper-level trough of low pressure near eastern Cuba and the southeastern Bahama Islands is predicted to slide west-northwest over the next few days. Wind shear over this low, current a prohibitively high 40 knots, is expected to relax to just 10 knots by Monday in the region surrounding Florida. This may allow a disturbance with a surface warm core to develop, according to phase space analyses from Florida State. However, since the upper atmosphere will still be cold, any development of this system will likely be subtropical in nature. If a subtropical storm does form, it may be fairly dry, like Subtropical Storm Andrea of May 2007. This storm ended up fanning fires in Florida, instead of putting them out. Water vapor loops show plenty of dry, continental air in the region, and it will take many days for the atmosphere to moisten enough to support formation of a subtropical depression.

Figure 1. Water vapor image showing moisture from a weak mid- to upper-level low of low pressure over the southeastern Bahama Islands, surrounded by a large area of dry air, and sandwiched between the polar and subtropical jet stream. Image credit: NOAA/SSD.

The GFS and NOGAPS models predict a subtropical depression could form by Tuesday, while the ECMWF shows development later in the week. The latest UKMET model forecast puts development Wednesday or Thursday near Haiti. The area of predicted development is sandwiched in a relatively narrow band of low wind shear between two branches of the jet stream. This is not a typical set-up for formation of a May tropical cyclone. With so much shear and dry air around, I put the probability of a subtropical depression forming next week at about 10%. Any developing system will also have to contend with the arrival Tuesday of a strong upper-level low pressure system that is expected to drop down over the northern Gulf of Mexico. The eventual track of any depression that forms is highly uncertain, and the models support tracks up the U.S. East Coast towards South Carolina, or up the west coast of Florida in the Gulf of Mexico.

Season's first tropical wave arrivesThe season's first tropical wave rolled off the coast of Africa yesterday, and is now located near 10N 20W, a few hundred miles off the coast of Africa, according to total precipitable water loops. Mid-May is a fairly typical time for these waves to begin moving across the Atlantic, though they usually don't start developing into tropical depressions until August. Last year was an exception, when Hurricane Bertha formed from a July tropical wave. Wunderground blogger Weather456 has been tracking the date of the first African wave each year since 2004, and these dates have ranged from May 2 to May 21. With Sea Surface Temperatures near average this year in the tropical Atlantic, an early season major hurricane in the eastern Atlantic like Bertha is unlikely.

Figure 2. The line of severe thunderstorms that spawned the Kirksville, MO tornado.

A wild night in Tornado AlleyNorthern Missouri took a hard hit by a powerful tornado last night, when a twister passed through Kirksville, killing three people. The tornado flipped cars and damaged 30 - 40 buildings as it tore through the north end of town. The Storm Prediction Center recorded 23 tornado reports across Missouri, Illinois, Oklahoma, and Kansas yesterday.

The Vortex2 field study, the world's largest-ever tornado research project, caught last night's tornado outbreak with its armada of 40 research vehicles and radars. You can read about yesterday's chase on our new featured Vortex2 blog. Our team of University of Michigan students caught some severe thunderstorms, but were forced by darkness to quit before the storms spawned tornadoes.

Portlight/wunderground shirts for saleThe portlight.org disaster relief charity is selling spiffy new shirts sporting the portlight and wunderground logos, to help raise funds for relief operations during the coming hurricane season. I expect that their services will be needed this year, and I encourage you to shell out the $20 to get this fine piece or wunderwear.

* URBAN FLOOD ADVISORY FOR MINOR FLOODING OF POOR DRAINAGE AREAS IN... LOWER KEYS IN MONROE COUNTY IN FLORIDA... THIS INCLUDES THE COMMUNITY OF KEY WEST...

* UNTIL 715 AM EDT

* AT 510 AM EDT LOCAL DOPPLER RADAR SHOWS A PERSISTENT LINE OF SHOWERS WITH EMBEDDED THUNDERSTORMS LIFTING NORTHWARD FROM THE ATLANTIC WATERS ADJACENT TO THE LOWER KEYS...ACROSS KEY WEST...INTO THE GULF WATERS.

RADAR ESTIMATES OF RAINFALL SHOW AROUND 2 INCHES OF RAIN HAS FALLENIN A NARROW STRETCH FROM THE ATLANTIC WATERS...ACROSS KEY WEST...ANDFURTHER INTO THE GULF WATERS. THE SENSOR AT KEY WEST INTERNATIONALAIRPORT HAS IN EXCESS OF 2.4 INCHES OF ACCUMULATION EARLY THISMORNING. AT THE WEATHER FORECAST OFFICE...ACCUMULATION IS IN EXCESSOF 2.1.

Good Morning......So, at present, and reguardless of whether a storm will generate or not (depending on which models you follow and whether they will untimately be accurate 2-3 days out), looks like Florida will continue to get some rain (combination of the "early" summer pattern from pop-up showers and any potential tropical or sub-tropical development)...Guess I'll be mowing the lawn this weekend and next........

Quoting ddbweatherking:Does anyone know the probability of a Hurricane (any category) hitting let's say in between Virginia and New Jersey? If you know of a website with that information, could you send me the link?Thanks!!!

Quoting jeffs713:I don't know exact probabilities, but I know it can vary from year to year, based on the setup of the A/B High in the Atlantic. Generally, it isn't a huge probability due to the topography of the coast and how far north it is. Over the past 4-5 years, I don't recall any hurricanes making landfall that far north. I will check a couple of my links at home, for reference. (on my lunch break in a few hours)

Thanks, i'm asking this because i am moving to Bethesda, MD in about a month and a half and i wanted to know my chances of excitement. But usually every few years a tropical storm hits that area right?

Quoting ddbweatherking:Does anyone know the probability of a Hurricane (any category) hitting let's say in between Virginia and New Jersey? If you know of a website with that information, could you send me the link?Thanks!!!

I don't know exact probabilities, but I know it can vary from year to year, based on the setup of the A/B High in the Atlantic. Generally, it isn't a huge probability due to the topography of the coast and how far north it is. Over the past 4-5 years, I don't recall any hurricanes making landfall that far north. I will check a couple of my links at home, for reference. (on my lunch break in a few hours)

Does anyone know the probability of a Hurricane (any category) hitting let's say in between Virginia and New Jersey? If you know of a website with that information, could you send me the link?Thanks!!!

UPPER TROUGH DEVELOPING IN THE GULF OF MEXICO SUNDAY/UPPER LOWDEVELOPING OVER CUBA ON MONDAY...THE NAM HAS TRENDED WEAKER WITH THIS GULF SYSTEM...AND A DAY LATERWITH ITS LOW DEVELOPMENT IN THE SOUTHEAST GULF OF MEXICO OVER ITSPAST DAY OF RUNS. THE GFS HAS TRENDED EASTWARD WITH THE GULFSYSTEM...AND HAS ALSO DELAYED ITS SURFACE LOW DEVELOPMENT BY 12-24HOURS OVER ITS PAST DAY OF RUNS. THE ECMWF HAD TRENDED EASTWARDWITH THIS SYSTEM OVER ITS PAST COUPLE DAYS OF RUNS...BUT ON ITS00Z RUN SHOWS A MORE DISTINCT SHORTWAVE MOVING INTO THE GULF OFMEXICO EARLY MONDAY...SIMILAR TO THE 00Z UKMET...AT A SLOWER PACETHAN THE 00Z GFS/NAM. WHILE THE GUIDANCE IS IN REASONABLEAGREEMENT WITH THE FORMING UPPER LOW ACROSS CUBA /WITH THE 00Z GFSCANADIAN AND UKMET WEAKER/...THE VARIOUS GUIDANCE DISAGREES WITHTHE SHORTWAVE ENTERING THE WESTERN GULF OF MEXICO...WITH THE NAMSHOWING THE LOWEST HEIGHTS AND THE FARTHEST NORTHWEST SURFACE LOWIN THE FLORIDA STRAITS/GULF OF MEXICO. THE NAM NORMALLY SHOWS ABIAS OF BEING TOO LOW WITH HEIGHTS NEAR SHORTWAVES THIS FAR INTOTHE FUTURE...AND BOTH THE GFS/NAM HAVE BEEN BACKING OFF ON THISLOW DEVELOPMENT WEST OF THE FLORIDA KEYS. AS THE 00Z ECMWF/00ZUKMET ARE BEGINNING TO SUPPORT THE 00Z GFS...WILL SUPPORT ACOMPROMISE OF THEIR SOLUTIONS TO ACCOUNT FOR THE GFS QUICK BIAS. THIS PREFERENCE ALSO WORKS OUT WELL WITH THE NEARLY CLOSED CYCLONENEAR CUBA EARLY MONDAY.

No matter what happens with this storm the models are predicting, central and south florida, if not the panhandle as well, will receive a lot of needed rainfall. UNLESS the system develops and moves to the East of Florida which would only limit the rain chances.

It really all depends on the timing of the systems that produce these storms. Just so happens this year all of the right ingredients are coming together at night. That's all.

Quoting Rlennon:Hello all, It looks like it about that time of year ago.I hope it is a busy tropical year but all fish storms. I have a question, there seem to be a lot of tornadoes in the nighttime around tornado alley. Is this the norm or just because the last few where at night it seem like the are more at night?

Hello all, It looks like it about that time of year ago.I hope it is a busy tropical year but all fish storms. I have a question, there seem to be a lot of tornadoes in the nighttime around tornado alley. Is this the norm or just because the last few where at night it seem like the are more at night?

there will be a broad area of low pressure at the surface in the southeastern GOM w/multiple vorticies and not a defined well organized warm core.....eventually if the area sits over the warmer waters of the easterm gom,a TC could form,but the waters just don't have the heat content to support any rapid development and sheer is only marginal,which is climatalogically about average for this time of year in our region,IMO....there we'll be plenty of rain in fL as a ULL forms along the trough,gets cut off and strengthens somewhere in the southeastern GOM..how long it sits,where it forms and sheer will determine if this area forms into a TD or TS,right now a STS at best is my opinion,thanks for reading!!!

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0915 UTC.

SEVERAL CYCLONIC CURLS ARE NOTED IN THE ACTIVE CONVECTION NEAR THE EPAC ITCZ...THE MOST NOTABLE ARE TWO AREAS OF LOW TO MID LEVEL TURNING A FEW DEGREES EITHER SIDE OF 110W. THIS GFS MODEL IS FORECASTING THE WRN MOST AREA TO BECOME BETTER ORGANIZED DURING THE NEXT SEVERAL DAYS. DUE TO ACTIVE AND PERSISTENT CONVECTION AND FAVORABLE UPPER LEVEL CONDITIONS...THIS AREA SHOULD BE WATCHED FOR POTENTIAL TROPICAL DEVELOPMENT.

Quoting jeffs713:Oss, 5 bucks says that "feature" in the gulf is another GFS ghost storm. The GFS has proven to be at least average at modeling once a storm is initialized... but I think most of us would do better with a dart board as far as cyclogenesis goes.

Not me, I don't believe anything until I see the spinning tops of the clouds on the SAT :)

It just stood out when I peeked at the loop, its there and gone instantly.

Quoting jeffs713:Oss, 5 bucks says that "feature" in the gulf is another GFS ghost storm. The GFS has proven to be at least average at modeling once a storm is initialized... but I think most of us would do better with a dart board as far as cyclogenesis goes.

Other reliable models are forecasting for some development. The two most reliable the GFS and ECMWF.

THE FORECAST EVOLUTION OF THE FLOW PATTERN ACROSS THE GULF OF MEXICO IS REASONABLY SIMILAR TO THAT OF MAY 18-23 OR MAY 25-28 OF 1991...WHEN A PAIR OF UPPER CYCLONES CLOSED OFF ONE AFTER THE OTHER...AND A BROAD SURFACE LOW MOVED FROM THE WESTERN CARIBBEAN INTO THE GULF OF MEXICO WHICH DEVELOPED A MORE DEFINED CENTER AS IT MOVED INTO THE ALABAMA COAST. IT IS BOUND TO BE A WET PATTERN ACROSS THE SUNSHINE STATE...AND ALONG WITH EXPECTED CONDITIONS DURING THE SHORT RANGE...SHOULD BREAK FLORIDA OUT OF THE DRY SEASON A COUPLE WEEKS EARLIER THAN NORMAL.

Oss, 5 bucks says that "feature" in the gulf is another GFS ghost storm. Also, note how this feature looks to be just rain, there isn't an apparent pressure drop attached to it. (all that rain is around 1012mb) The GFS has proven to be at least average at modeling once a storm is initialized... but I think most of us would do better with a dart board as far as cyclogenesis goes.

Quoting foggymyst:Ike, so in looking at that GFS 6 days from now, the system, wave..cloud..seems to slow down or even stall? Could be good from the drough in Florida. Much rain over a period of time vs. a quick hot rainstorm.

The immediate hope for Florida is afternoon thunderstorms and the trough coming in early next week.

As far as anything topical, too early to determine if anything ever will develop and where it will go, if it does....just my opinion....

I have a great deal of respect for you Storm-Now some one encourage that rain to come a little closer to my house, please. West and central Texas are still in drought conditions and we haven't had any rain where I live since the flooding ones a few weeks back. It is getting a bit too dry again.

Ike, so in looking at that GFS 6 days from now, the system, wave..cloud..seems to slow down or even stall? Could be good from the drough in Florida. Much rain over a period of time vs. a quick hot rainstorm.

You guys dont understand early (tropics) model runs in a season. They are not consistant and usually bullish on anything tropical developing. Also posting where something might form in the tropics over 3 days from now is no good. Models usually want to find something..form it..and push it north in May...but nothing happens..I would wait for a area of intrest within 2 days with models support in that area from the GFS,Ukmet and Euro.. right now the low everyone is trying to find with the models isnt set in stone and the models will keep delaying the formation till nothing happens.